Shutoff valves are provided in air distribution systems of conventional cargo aircraft in order that the air supply to the cargo compartment or the cargo compartments, also called cargo decks, can be shut off in the event of a fire in the cargo compartment. Passenger aircraft do not have shutoff valves of this kind, as the air supply cannot be shut off in these aircraft, even in the event of a fire in the passenger compartment, as breathing air would otherwise no longer be available to the passengers. The above-mentioned shutoff valves, which are integrated into cargo aircraft, are so-called two-position valves, i.e. they are either completely closed in order to interrupt an air supply to the cargo compartment or completely open in order to release the air supply to the cargo compartment. If there is no abnormal occurrence (fire, etc.), a constant volume of fresh air is therefore supplied to the cargo area of a conventional cargo aircraft irrespective of the transported cargo. As is usual in aircraft construction, this fresh air comes from the engine or the engines of the aircraft and is also called bleed air, as it is bled or tapped from a compressor stage of the aircraft turbines. As a result, the production of bleed air of this kind costs fuel, for the bleed air volume is no longer available to the aircraft engine for combustion and must therefore be post-produced by the aircraft engine.
The object of the invention is to minimize the bleed air requirement of a cargo aircraft in order thus to reduce its operating costs.